The present invention relates to digital computer memory means and, more particularly, to a novel method and apparatus for randomly rotating a particular block of memorized data among a plurality of possible data site blocks to prevent undesirable data deterioration.
Known memory devices, such as the BEAMOS (BEam Addressed Metal Oxide Semiconductor) memory device, utilize a storage target, such as that disclosed in U.S. Pat. No. 3,761,895 to G. W. Ellis et al., issued Sept. 25, 1973 and assigned to the assignee of the present invention, which may be prone to at least two effects which may tend to reduce their data reliability when utilized in computer memory systems. These effects are: data site fatigue, defined as the permanently degraded performance of a data site (e.g., reduced signal output, reduced storage time, and so forth) after repeated usage of that data site; and adjacent site disturbance, defined as loss of information in a particular data storage site due to repeated accesses to other data sites in the memory. It should be understood that digital memories utilizing technologies including, but not limited to, MNOS (metal-nitride-oxide-semiconductor) transistors, thin film magnetic devices and charge storage memory devices may all suffer reduced data reliability from these or similar potential effects. A method, and apparatus implementing such novel method, for minimizing the effects of fatigue and adjacent site data disturbance in a memory (capable of having the data at any data bit site rewritten at electronic speeds responsive to external address and data stimuli) is extremely desirable.